Seafood has long been recognized as an important component of a healthy diet. Seafood contains high quality, complete protein and an important array of nutrients, while it is low in calories, cholesterol, and saturated fats. The health benefits of omega-3 fatty acids found primarily in fish have been clearly documented. U.S. farm-raised seafood is an important center of the plate choice that can replace high calorie, high saturated fat alternatives. However, fish, other than breaded and fried products, is very seldom consumed by American children and many adults for a variety of reasons. Most health and nutrition organizations recommend that Americans increase their consumption of seafood to maintain good health. In spite of those recommendations, annual seafood consumption in the United States is declining and in 2013 it slumped to a 30 year low of 14.4 pounds per capita. That is less than half of the consumption level recommended by government agencies and health-related organizations.
Cardiovascular disease, type-2 diabetes, coronary heart disease, overweight and obesity are rampant in the United States. Attempts to deal with these epidemics by the increased use of drugs have resulted in, what many consider to be, an overmedicated society. Some simple changes in diet might provide a better answer. Given the growing list of positive health benefits, it is important that the nutrition and healthcare communities have science-based information about farm-raised seafood to share with their constituents. Many people who would like to improve their diet have misconceptions about seafood and they look to professionals for answers. It is especially important to develop good nutrition practices in children who will form life-long dietary habits and adults who can benefit from better heart health.
Omega-3 Fatty Acids
There are three types of omega-3 fatty acids found in foods. One type is alpha-linoleic acid (ALA) found in some oils including soybean, rapeseed (canola), walnut, and flaxseed oils and in some green vegetables such as Brussels sprouts, kale, spinach, and greens.The other types of omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA), are found primarily in fatty fish and other marine products. EPA and DHA are the most potent fatty acids and provide most of the health benefits that have been studied to date. The body does convert some ALA to EPA and DHA, but not efficiently. This is an important point because many healthconscious patients don’t understand that there is an important difference between ALA and EPA/DHA. Heart disease and stroke remain the number 1 and number 4 causes of death in the United States. Studies indicate that EPA and DHA may play important roles in reducing those deaths.
The possible benefits provided by a diet containing EPA and DHA include:
- decreased risk for thrombosis, which can lead to heart
attack and stroke.
- decreased triglyceride and remnant lipoprotein levels.
- decreased rate of growth of atherosclerotic plaque.
- slightly lowered blood pressure.
- reduced inflammatory responses
- improved endothelial function.
Although many people rely on fish oil or other marine oil supplements to provide important omega-3 fatty acids, actually consuming a fish meal at least twice a week provides a wealth of other benefits. Substituting fish or shellfish for other center of the plate choices that may be high in calories, cholesterol, and saturated fats can help build a healthier lifestyle. Farm-raised salmon, trout, and oysters are excellent sources of EPA and DHA. Dariush Mozaﬀarian and Eric Rimm of the Harvard School of Public Health calculated that eating about 2 grams per week of EPA/DHA, about one or two servings of fatty fish a week, reduces the chances of dying from heart disease by more than one-third. (1)
Not all Proteins are Created Equal
Complete or high quality proteins contain all of the essential amino acids that are necessary for growth and tissue repair. These are the amino acids that cannot be synthesized by the body and must be ingested as part of the diet. Animal proteins such as fish, meat, poultry, cheese and eggs contain those essential amino acids. When choosing a high quality source of protein, it is important to consider the other nutrients that come along with it. Some meats, although they are excellent sources of protein, contain high levels of saturated fats and cholesterol. Other good protein sources like cheese and peanut butter can be high in calories. The important point is that seafood is a high quality protein while it is low in calories, cholesterol, and saturated fats. An added benefit is that it is easier to digest than many other animal proteins because it contains less connective tissue.The Dietary Guidelines for Americans 2010 includes a quantitative recommendation of 8 or more ounces of seafood per week (less for young children). That is about 20% of the total recommendation for protein foods. It is important to choose a variety of seafood rather than consuming the same product over and over which can become boring.
The current recommended limit for daily sodium intake is less than 2,300 milligrams for the general adult population and higher risk groups would benefit by further reducing their sodium intake to 1,500 milligrams per day. Fish are naturally low in sodium and even those species with the highest sodium levels contain less than 100 milligrams per 3 ounce cooked portion. Most shellfish generally have more sodium, ranging from 100 to 500 milligrams per 3 ounce cooked serving. Herbs and spices are flavorful substitutes for added salt. Some processed or frozen seafood products may contain significantly higher sodium levels. It’s a good idea to carefully read ingredient or nutritional labels for processed products to determine their sodium content.
High Risk Groups and Raw Fish and Shellfish
Molluscan shellfish, including clams, oysters, and mussels, are filter feeders and can accumulate marine bacteria and viruses. One such type of bacteria, called Vibrio vulnificus, is naturally occurring in the marine environment, and is found most often in waters of the southern United States during the summer months. Vibrio vulnificus can also be carried by finfish. In fact, people can also be infected simply by swimming in marine waters if they have open wounds. These organisms can cause fever, chills, vomiting, abdominal pain, nausea and other gastrointestinal symptoms. In a few high-risk individuals, the symptoms may be more severe or even life threatening. High risk individuals include those who may have a compromised or weakened immune system because of health conditions such as liver disease (hepatitis, cirrhosis, alcoholism, or cancer), iron overload disease (hemochromatosis), diabetes, cancer (including lymphomas, leukemia, Hodgkin’s disease), chemotherapy patients, HIV infection, and stomach or intestinal problems (decreased stomach acidity), and certain groups such as the elderly, pregnant women and young children.These individuals should not eat raw or partially cooked finfish or shellfish. Since thoroughly cooking oysters, clams, mussels, and finfish will destroy the bacteria, they can continue to be enjoyed in many fully cooked preparations.
A well-balanced diet that includes a variety of fish and shellfish can contribute to maternal health and children’s proper growth and development. Women should recognize that avoiding seafood altogether is likely to harm their unborn babies’ brain and nervous system development. Therefore, women and young children should include fish and shellfish in their diets because of the many nutritional benefits. Some studies have shown that modest fish consumption (2 meals per week) during pregnancy may actually improve motor skills, brain function, and communication in young children. Other research suggests that seafood consumption may help mothers carry their babies to full term and avoid low birth weight. Regular seafood consumption has also been implicated in mood improvement, especially in cases of post-partum depression. The nutritional value of seafood is of particular importance during fetal growth and development, as well as in early infancy and childhood. Some evidence indicates that intake of omega-3 fatty acids, in particular at least 8 ounces of seafood per week for women who are pregnant or breastfeeding is associated with improved infant health outcomes. The Dietary Guidelines for Americans 2010 recommends that women who are pregnant or breastfeeding consumer at least 8 and up to 12 ounces of a variety of seafood each week. Those selections should be made from the many species that are not considered to be high in methyl mercury. Obstetricians and pediatricians should provide guidance to women who are pregnant or breast feeding to help them make healthy food choices that include seafood. The key to enjoying great fish and shellfish during and after pregnancy is to eat a variety of seafood farm-raised in the USA. Federal, state, and local regulations help ensure that no harmful drugs, chemicals, hormones, and antibiotics are used during production. http://hmhb.org/pnwg/topics/baby-brain-and-eye-development/
Low Mercury Seafood
Mercury occurs naturally in the environment as a result of volcanic activity and can also be released into the air through industrial emissions. Some long-lived, deepwater fish tend to accumulate more mercury that other species. For these reasons, the U.S. Food and Drug Administration (FDA) has issued a mercury advisory for a very limited target audience including pregnant women, women who may become pregnant, nursing mothers, and small children. If you are not in this target audience, the advisory does not apply to you. It is recommended that individuals in the target audience avoid the consumption of shark, tilefish (harvested in the Gulf of Mexico), swordfish, and king mackerel and limit the consumption of albacore (white) tuna to 6 ounces per week. Chunk light tuna is not restricted because it is a different species. Many of the fish and shellfish considered low mercury including shrimp, channel catfish, tilapia, trout, and salmon are farm-raised.The vast majority of the seafood consumed in the United States is considered low mercury.
The Cholesterol Myth
Some people believe that all cholesterol is bad, but actually our bodies need cholesterol for a variety of functions including maintaining a healthy nervous system. Many consumers shy away from shellfish because they believe that they are high in cholesterol. Earlier methods for measuring cholesterol were found to produce artificially high results because other sterols were being measured as well. Clams, oysters, and mussels are naturally low in cholesterol and are packed with a variety of important health benefits including omega-3 fatty acids, complete protein, and important minerals such as zinc and iron.
Shrimp contain a somewhat higher level of cholesterol (about 170 milligrams per 3 ounce cooked serving), but there seems to be a complex set of interactions among the fats. The omega-3 fatty acids in shrimp tend to improve the ratio of “good” cholesterol (High Density Lipoprotein-HDL) to “bad” cholesterol (Low Density-LDL) in the body. Although shrimp contain a slightly higher level of cholesterol than many meat and poultry products, they often contain less total fat and saturated fats.
The American Heart Association recommends consuming no more than 300 milligrams of dietary cholesterol per day. One serving of shrimp contains just about half of the daily recommendation.
Organic Contaminants including PCBs and Dioxin
The main dietary source of organic contaminants in seafood is sport fish caught in contaminated waters. Sports anglers tend to eat many of the same species of fish caught in the same location. This can increase any potential risk.
Levels of PCBs and dioxins in commercial fish and shellfish are very low, similar to levels in meats, dairy products, and eggs. More than 90 percent of the PCBs and dioxins in the U.S. food supply come from non-seafood sources. People who are concerned about PCBs and other fat soluble contaminants can take steps to reduce any potential intake. Since contaminants accumulate slowly over a long period of time, select smaller fish.
Cooking techniques that allow fats to drip away from the fish such as grilling, broiling, or baking on a rack can also be used.
Antibiotic, Hormone and Drug Use in U.S. Farm-Raised Seafood
U.S. farm-raised seafood is grown under strict food safety and environmental regulations. In the United States, it is illegal to use antibiotics or added hormones as a growth enhancer. Very few drugs have been approved for use for food fish and those drugs must be used under the direction of a licensed veterinarian only in response to a disease concern.Treating sick animals is a tenet of U.S. animal welfare standards. The FDA’s Center for Veterinary Medicine (CVM) works with government agencies and aquaculture associations to maintain the safety and effectiveness of approved drugs. Before a drug is approved for use in U.S. aquaculture, it must be shown that it will not harm the environment or public health. Strict drug withdrawal times are enforced to help assure public safety.
Approximately 2.8% of the U.S. population has an allergic reaction to either finfish, shellfish, or both. Most people experience their first allergic reaction as adults.The most common finfish allergies involve salmon, tuna and halibut. Of that list, only salmon is currently farm-raised. Shellfish can be divided into mollusks (clams, oysters, mussels, snails, etc.) and crustaceans (crabs, lobsters, and shrimp). Allergic reactions to crustaceans tend to be the most severe. Mollusks are not considered to be major allergens. People who are allergic to one group of shellfish may not be allergic to the other. Many allergists recommend allergen testing prior to any consumption of shellfish. Some foods contain hidden seafood ingredients. Since allergic reactions can be severe, label reading is important.
Foods that contain anchovies
- Worcestershire sauce
- Barbecue sauces made with Worcestershire
- Caesar salad and Caesar dressing
Other foods that contain fish
- Caviar and fish roe (fish eggs)
- Products like surimi, an imitation crabmeat, sometimes used in sushi
- Fish sauce, oils, and some gelatins